Only went back 3 pages and didn't see this addressed...
The 'anchor point' for the 5x10 and 5x15(or 20, can't remember) is off which necessitated my having to use multiple 5x5 tiles. On the 5x10 the anchor point is shown as being about 5 meters away from the tile itself while it appears to be 10 or more meters from the longer version.
Like I said, used multiple 5x5's instead, but would think it would result in faster loading if the longer ones could have been used.